If the PH of a Solution is Increased from PH

Question

If the pH of a solution is increased from pH 5 to pH 7, it means that the
A) concentration of H⁺ is twice (2X) what it was at pH 5.
B) concentration of H⁺ is one-half (1/2) what it was at pH 5.
C) concentration of OH⁻ is 100 times greater than what it was at pH 5.
D) concentration of OH⁻ is one-hundredth (0.01X) what it was at pH 5.
E) concentration of H⁺ is 100 times greater and the concentration of OH⁻ is one-hundredth what they were at pH 5.

Accepted Answer

The pH scale is logarithmic, so an increase from pH 5 to pH 7 means the concentration of H⁺ ions decreases by a factor of 100, and the concentration of OH⁻ ions increases by a factor of 100.